Method of and apparatus for braiding



Feb. 22, 1949.

' INVENTOR B. w L RGH ATTORNEY B. W. LERCH METHOD AND-APPARATUS FORBRAIDING Feb. 22, 1949.

Filed Oct. 9, 1947 2 Sheets-sheet 2 FIG. 2

FIG. 3

INVEN TOR 8W. LERCH 5 A T TORNE V Patented Feb. 22, 1949 METHOD OF ANDAPPARATUS FOR BRAIDING Brooke W. Lei-ch, Baltimore, Md., assignor toWestern Electric Company, Incorporated, New York, N. Y., a corporationof New York Application October 9, 1947, Serial No. 778,773

6 Claims.

This invention relates to methods of and apparatus for braiding, and hasfor an object thereof the provision of new and improved methods of andapparatus for braiding.

A method illustrating certain features of the invention may includebraiding metallic strands over an elongated article, and overforming thestrands on the article so that the strands are substantially unstrainedin their braided posi tions.

An apparatus illustrating certain features of the, invention, and bymeans of which methods embodying features of the invention may bepracticed, includes means for advancing an elongated article along apredetermined path, mean for braiding a plurality of strands, at leastsome of which are metallic, into a covering around an elongated articleso advanced, and means for twisting the covered core through apredetermined angle about the longitudinal axis thereof in such adirection that the metallic strands tend to be Wound more closely uponthe core, whereby the metallic strands are overformed on the core andcling closely to the core.

A complete understanding of the invention may be obtained from thefollowing detailed description of a method and apparatus formingspecific embodiments thereof, when read in conjunction with the appendeddrawing, in which:

Fig. 1 is a fragmentary, elevational view of an apparatus illustratingcertain features of the invention;

Fig. 2 is an enlarged, horizontal section taken along line 2--2 of Fig.l, and

Fig. 3 is an enlarged, fragmentary elevation takenalong line 3-3 of Fig.2.

Referring now in detail to the drawing, a generally elliptical core I!)(Fig. 2) which includes conductors i [-1 l enclosed in an insulatingcovering l2 generally elliptical in shape is advanced through a braideri l of a well known type. The braider I4 rotates bands of steel wiresl6--l6 in one direction around the core it, rotates bands of cottonstrands Iii-l8 around the core in the opposite direction, andinterweaves the bands of steel wires with the bands of cotton strandsinto a braided covering 20. Hence, the steel wires l6i 6 are all Woundaround the core I!) in a single direction.

The core H! with the braided covering 20 thereover is advanced through agenerally elliptical opening 22 in a die 24, which holds the portions ofthe core Ii] and the braided covering 20 passing through the opening 22in predetermined positions. The core l and the braided covering 26 thenare advanced through a generally elliptical opening 26 in a die 28,which is spaced slight- 1y above the die 2%, as viewed in Fig. 1. Theopening 25 is complementary in cross section to the cross section of thecore Iii and the braided covering thereover, and the major axis of theopening 26 is at a substantial angle with respect to the major axis ofthe opening 22 in the die 24. Hence, the portion of the core i5] and thecovering 26 between the die 24 and the die 28 is twisted through thisangle. This twisting tends to wind the steel wires lt-i6 more tightlyupon the core M, which action is permitted by the resilient covering It,so that, when the wires spring from their residual resiliency back topositions in the untwisted portion of the covered core above the twistedportion thereof, a viewed in Fig. 3, the wires are substantiallyunstressed.

Operation In the operation of the apparatus described hereinabove toaccomplish one method embodying the invention, the core l0 (Fig. l) isadvanced upwardly through the braider M which interbraids the steelwires l6-ii with the cotton strands 18-18 to form the braided covering20, and. as the wires iii-i6 are applied to the core H! in. a clockwisedirection, as viewed in Fig. 2, they are tensioned to apply them quiteclosely to the core 10. As the braided covering 28 is advanced throughthe dies 24 and 28, the dies twist the core and the braided coveringthrough the angle by which they are displaced to wind temporarily thesteel wires iE-l-ii more tightly around the coreiii and to embed thempartially and temporarily in the covering l2 as they are so wound. Thistemporary winding bends the wires lG-IB sufi'lciently beyond theirelastic .limits to cause them to stay close to the insulating coveringi2 when the core Iii and the covering 20 untwist as they pass out of thedie 28. As a result, the braided covering 20 does not unravel, and fitsclosely on the core even if the ends of the covering are not tied down.

The above-described method and apparatus serve to form tightly braidedcovering from me tallic and cotton strands upon cords. Theabovedescribed apparatus is simple in construction and inexpensive inits operation. The steel wires Hil6 need not be highly tensioned as theyare braided upon the core it so that a light braider may be used anddamage to the insulating covering 12 of the core [0 is prevented.

What is claimed is:

1. The method of braiding coverings upon cores, which comprisesadvancing a core in a predetermined direction along a predetermined pathrotating a plurality of non-metallic strands in a predetermineddirection around said core, rotating a plurality of metallic strandsaround the core in a direction opposite to that in which thenon-metallic strands are rotated, interbraiding the metallic strandswith the non-metallic strands to form a braided covering over the core,and twisting the core and the covering in such a direction as to windthe metallic strands more tightly around the core so that the metallicstrands tend to cling to the core.

2. An apparatus for braiding coverings upon cores, which comprises meansfor advancing a generally elliptical core along a predetermined path,rotating a plurality of metallic strands around the core at apredetermined point along said path in a predetermined direction, meansfor rotating a plurality of non-metallic strands around the core at saidpoint in the direction opposite to that in which the metallic strandsare rotated, interbraiding the metallic strands with the non-metallicstrands to form a braided covering upon the core, a generally ellipticaldie positioned at a second point along the path through which thecovering and the core pass for holding the portion of the covering andthe core passing therethrough against rotation about the longitudinalaxis of the core, and a second generally elliptical die spaced from thefirst generally elliptical die and held in a position in which the majoraxes of said dies form a substantial angle therebetween for causing theportion of the covered core between said dies to be twisted through saidangle, whereby the portions of the metallic strands upon the portion ofthe core between said dies are temporarily wound more tightly upon thecore.

3. The method of forming coverings upon cores, which comprises applyingmetallic strands around a core in a predetermined direction with apredetermined lay, advancing the core and the strands along apredetermined path, holding the core and the strands against rotationabout the axis of the core at a predetermined point in the path, andholding the core and the strands at a point in the path spaced from thefirst-mentioned point in positions in which the portions of the core andthe strands between said points are twisted in such a direction as towind the strands upon the core more tightly so that the strands areoverformed upon the core and lay closely thereon.

4. The method of forming coverings upon core including soft elasticexterior portions, which comprises advancing such a core along apredetermined path, serving closely a plurality of metallic strandsaround the core in a predetermined direction at a predetermined lay,holding the portions of the strands and the core at one point in saidpath against revolution about the longitudinal axis of the core, guidingthe portions of the strands and the core from said point in a twisteddirection such as to wind the strands more tightly upon the core for ashort predetermined distance from said point, and advancing the strandsand the core from the lastmentioned point in the path in a non-twistedcondition.

5. An apparatus for covering cores, which comprises means for advancingan eccentric core having an elastic outer portion continuously in apredetermined direction along a predetermined path, means for serving aplurality of metallic strands around an eccentric core advanced alongsaid path, an eccentric guide positioned at one point in said path forholding the portions of the strands and the core passing through saidpoint in predetermined positions, and a second eccentric guide spacedfrom the first-mentioned guide for guiding the portions of the core andthe strands between the first-mentioned guide and the second-mentionedguide through a twisted path, whereby the strands are temporarily woundmore closely upon the core so that the strands are overformed and arelayed closely on the core.

6. An apparatus for covering cores, which comprises means for advancinga generally elliptical core along a predetermined path, serving aplurality of metallic strands around the core at a predetermined pointin the path in a predetermined direction, a generally elliptical diepositioned at a second point in the path through which the strands andthe core pass for holding the portions of the strands and the corepassing therethrough against rotation about the longitudinal axis of thecore, and a second generally elliptical die spaced from the firstgenerally elliptical die and held in a position which the major axes ofthe dies form a'substantial angle therebetween for causing the portionof the covered core being advanced from one die to the other die to betwisted through said angle in such a direction that the portions of themetallic strands upon that portion of the core are temporarily woundmore tightly upon the core.

BROOKE W. LERCH.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 787,383 Klein Apr. 18, 19051,671,951 Angell May 29, 1928 1,990,071 Green et al Feb. 5, 19351,990,514 Angell Feb. 12, 1935 1,992,707 Lloyd Feb. 26, 1935 2,037,506Ensinger et al Apr. 14, 1936

